Involvement of the scalp may be minimal (few plaques) or more significant. The entire scalp can be involved.

Hair loss may be seen with significant involvement of the scalp, and is non-scarring. Hair should regrow when the psoriasis clears.

Areas Affected

Psoriasis affects the skin, especially extensor surfaces and also the scalp, body
folds, and nails. The scalp may be the most frequently involved area. Approximately
15%-30% of patients have an associated arthritis.

Cause

There is a genetic basis to psoriasis with an increasing risk of developing the
disease if one or both parents have psoriasis. The activated T cell plays a pivotal
role in the pathogenesis of the disease.

Symptoms

Itch

Psychosocial distress (markedly affects quality of life)

Hair loss with severe involvement

Classic Lesion

The classic lesion is a well-demarcated, erythematous plaque with a silvery
scale. When the scale is removed, bleeding points are seen (Auspitz sign).
Psoriasis can develop after trauma and lesions worsen with rubbing or scratching
(Koebner phenomenon).

Forms/Types of Lesions

Chronic Plaque

Erythrodermic

Pustular – Localized or Generalized

Guttate

Inverse

Triggers

Stress

Hormones – Pregnancy

Trauma

Drugs – Beta-Blockers, Lithium, Anti-Malarials

Systemic Steroid Withdrawal

Infections – Viral and Streptococcal

Differential Diagnoses

Seborrheic Dermatitis – common

Lichen Planus – unlikely

Fungal Infection – unlikely

Lupus Erythematosus – unlikely

Scalp Psoriasis vs. Scalp Seborrheic Dermatitis

Scalp Psoriasis

Scalp Seborrheic Dermatitis

Silvery white, dry scales

Yellow, greasy scales

Well demarcated

Poorly defined

Can extend onto forehead (check nails, extensor surfaces)

Remains within scalp hairline (check eyebrows, sides of
nose, ears)

Seborrhiasis

Seborrhiasis presents with features of both psoriasis and seborrheic dermatitis. Psoriasis of the scalp is primarily
treated locally with topical treatments. Systemic therapies are usually reserved for more widespread or severe forms of
psoriasis.

Recalcitrant Psoriasis

Resistant or recalcitrant psoriasis of the scalp may require intralesional injections of corticosteroids, and less frequently
a systemic treatment.

Treatments for Psoriasis

Topicals

Tar

Coal Tar
- Shampoo
- Compounded with corticosteroids

Wood Tar
- Anthralin (Infrequently used in North America; still popular in Europe)

Warnings

Conclusion

Psoriasis remains a therapeutic challenge. Involvement of the scalp can be minimal (“dandruff”) or more significant
and difficult to manage. Gentle treatment, reducing trauma, and treating the inflammation and pruritus will improve
therapeutic results.